That sounds bad, alright. Hurting people, obviously, and then messing with their heads too? Whatever that means, it can't be good.

Frisk glances around the piles of stuff closest to them. They're not lucky enough to have an old couch or anything nearby, but there's some crates and boxes. They move to sit on one, gesturing the old guy to come take a seat nearby. If this place is safe, they should stay here to talk. And they're going to talk about it. Frisk doesn't just let people hurt each other when they can help it.

Who are they? Obviously, they are choosing to completely ignore Greg's warning.